Hosta species delimitation has been problematic due to a long history of cultivation, hybridization, and selection, particularly in Japan, from the eighth century onwards (W. G. Schmid 1991). Hosta nomenclature is further complicated because many names are based on types of garden origin or sports originating among wild populations. Earlier taxonomic treatments were largely based on materials cultivated regionally in Japan (N. Fujita 1976), North America (L. H. Bailey 1930), Korea (M. G. Chung 1990; M. G. Chung and J. W. Kim 1991), and Europe (N. Hylander 1954). Hosta can be considered to comprise as few as 23–26 species (F. Maekawa and K. Kaneko 1968; N. Fujita 1976), or 40 or more if a stricter species concept is applied (A. Huxley et al. 1992; F. Maekawa 1940; W. G. Schmid 1991).

Well over 1000 cultivars have been recorded with the International Registration Authority. Primarily used in temperate shade gardens, these cultivars feature various combinations of leaf size, shape, color, variegation, and texture (P. Aden 1988; D. Grenfell 1996, 1998; N. Hylander 1954; K. Kubitzki 1998b; W. G. Schmid 1991). While Hosta is mainly of ornamental importance economically, the leaves of some species are cooked and eaten in Korea and Japan, thus depleting local populations.
Funkia, a later generic name proposed by Sprengel for these plants, is an illegitimate later homonym of Funckia Wildenow, and the family name Funkiaceae based upon it is therefore invalid (B. Mathew 1988). However, “funkia,” from the vernacular Japanese fukurin fu, long ago passed into many European languages as another common name for Hosta.